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Microwave and Infrared Dielectric Response of Temperature Stable (1− x ) BaMoO 4 – x TiO 2 Composite Ceramics
Author(s) -
Guo Jing,
Zhou Di,
Wang Hong,
Chen Yuehua,
Zeng Yi,
Xiang Feng,
Wu Ying,
Yao Xi
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04760.x
Subject(s) - materials science , rutile , dielectric , analytical chemistry (journal) , ceramic , microwave , scheelite , atmospheric temperature range , permittivity , sintering , chemical engineering , composite material , tungsten , chemistry , optoelectronics , metallurgy , organic chemistry , engineering , physics , quantum mechanics , meteorology
The (1− x ) BaMoO 4 – x TiO 2 ( x = 0.0, 0.2, 0.3, 0.338, 0.4, 0.5, 0.66) ceramics were synthesized by the conventional mixed‐oxide process. The sintering behaviors, phase composition, chemical compatibility with silver, and microwave dielectric properties of pure (1− x ) BaMoO 4 – x TiO 2 ceramics and 0.662 BaMoO 4 –0.338 TiO 2 ceramic with H 3 BO 3 – CuO addition were studied. Infrared reflectivity spectra of (1− x ) BaMoO 4 – x TiO 2 (0.2 ≤ x ≤ 0.4) composites were measured in the range of 50–4500 cm −1 at room temperature. X ‐ray diffraction analysis reveals that scheelite BaMoO 4 and rutile TiO 2 phase coexist with each other at 1275°C and both of them do not react with silver ( Ag ) at 850°C. When the mole fraction of TiO 2 ( x value) is 0.4, a temperature stable microwave dielectric material is obtained, with ε r = 13.8, Q × f = 40 500 GHz ( f = 8.02 G), and τ f = −6.13 ppm/°C. Complex dielectric spectra gained from the infrared spectra were extrapolated down to microwave range, and they were in good agreement with the measured microwave permittivity and dielectric losses. With 5 wt% H 3 BO 3 and 1 wt% CuO addition, the 0.662 BaMoO 4 –0.338 TiO 2 ceramics can be sintered well below 900°C, and possess good microwave dielectric properties with ε r = 14, Q × f = 48 360 GHz, and τ f = +13.9 ppm/°C.